If I just use the SATA I ports that are on the old motherboard, would that be as faster then?
SSDs improve over HDDs by decreasing latency (time drive takes to find data) and increasing read and write speeds (faster game loads and program installs/FRAPS recordings respectively). I don't think latentcy will be affected too much, but SATA I will be saturated, and SATA III may have a large 'overhead' (use of system resources slowing the whole PC)
And what is TRIM?
TRIM basically prepares 'deleted' parts of the drive to have data written over the top of it. Without TRIM, the drive will have to do it as you are writing the data which will significantly decrease the performance of the drive.
I have another question. I bought 2 Western Digital VelociRaptors hard drives, 3 years ago, at a good price and have remained to this day in storage. Do you think the drives are ok?
WD raptors are gods among traditional HDDs, but even they pale in comparison to an SSD. If they haven't been jostled around too much they should work fine.